. >> reporter: they clashed on wall street, whether banks should be too big to fail, and medicare. >> cutting $716 billion from medicare to be able to balance the additional cost of obama care is, in my opinion, a mistake. >> if you repeal obama care, and i have become fond of this term, obama care, if you repeal it, what happens is those seniors right away are going to be paying $600 more in prescription care. >> reporter: the fiercest exchange over health care and jobs. >> i just don't know how the president could have come in to office facing 23 million people out of work, rising unemployment, an economic crisis at the kitchen table and spend his energy and passion for two years fighting for obama care instead of fighting for jobs for the american people. >> we did work on this alongside working on jobs, because this is part of making sure that middle class families are secure in this country. >> reporter: president obama on defense, romney challenging his record, as both now wait to see if this exchange has any impact on voters. it had impact online. on twitter, the most tweeted e